Ultra Flex Seam Sealer & Adhesive is a solvent- and isocyanate-free multi-purpose sealant. It may be applied by caulking gun or spray equipment and is easily extruded and tooled. 4172 is a moisture curing sealant developed for automotive and industrial applications requiring elasticity, high strength and excellent adhesion. The product is tough, elastic and waterproof. It bonds aggressively to steel, aluminum, galvanized metal, fiberglass, urethane, epoxy, polyester, water-based primers, glass, Styrofoam and many plastics.